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Calcium release from InsP 3 ‐sensitive internal stores initiates action potential in Chara
Author(s) -
Biskup Bernhard,
Gradmann Dietrich,
Thiel Gerhard
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00600-6
Subject(s) - chara , excitatory postsynaptic potential , inositol , biophysics , inhibitory postsynaptic potential , calcium , chemistry , voltage clamp , phospholipase c , ryanodine receptor , biochemistry , membrane potential , biology , botany , receptor , neuroscience , organic chemistry
Neomycin and U73122 are known to suppress inositol 1,4,5‐trisphosphate (InsP 3 ) production by inhibition of phospholipase C. We studied the effects of these inhibitors on the excitatory currents, I ex , in Chara corallina under voltage‐clamp conditions. Computer simulations of the experimental effects by a minimum model for the excitatory reaction pathway allow the assignment of the inhibitory effects to one specific reaction step, i.e. the release of Ca 2+ from InsP 3 ‐sensitive internal stores. In contrast, the inhibitory effect of La 3+ on I ex suggests inactivation of Cl − channels. Furthermore, ryanodine‐sensitive Ca 2+ stores seem to be irrelevant for electrical excitation in Chara .